Recent Advances in Tunable Metasurfaces and Their Application...
If the absorption losses can be neglected, 𝜺ε is a Hermitian matrix. Thus, the permittivity tensor 𝜺ε becomes anisotropic with complex out of diagonal elements 𝜺′𝒊𝒋=𝜺′𝒋𝒊 ε′ij=ε′ji¯: 𝜺= ⎜⎜⎜⎜⎜⎜⎜𝜺𝒙𝒙𝜺𝒙𝒚−𝒊𝒈𝒛...